Research utilizing the isotope facility at the Biological Laboratories encompasses, among other topics: biosynthesis of bacterial cell walls; plant cytodifferentiation; biochemistry of genetic recombination; host-induced virus modification and restriction; mode of action of gene repressors; structure and function of RNA polymerase; mechanism of transfer and ribosomal RNA synthesis; the ribosome cycle in protein synthesis and its control: action of diphtheria toxin; replication of DNA; plastid biochemistry; photosynthesis; biochemistry of insect development; hormonal regulation and chemistry.